This invention relates to a metal fixing member for fixing a connector to a wiring board and also to a connector provided with the metal fixing members.
One known related metal fixing member for fixing a connector to a wiring board is formed by bending a strip-like metal sheet into a generally cross-sectionally L-shape, and one metal piece portion, extending from a generally-central bent portion in a longitudinal direction, is affixed to an outer surface of a connector housing, while the other metal piece portion is fixedly secured to the wiring board by soldering or the like, thereby fixing the connector to the wiring board (see, for example, JP-A-8-130055 (Pages 3 to 4, FIG. 1) and JP-A-9-161912 (Pages 2 to 4, FIG. 1)).
FIG. 9 shows a metal fixing member which is substantially identical in structure to those disclosed in JP-A-8-130055 and JP-A-9-161912.
As shown in FIG. 9, the metal fixing member 1 includes a board fixing portion 3 for being fixed to a board surface of a wiring board, and a housing mounting portion 2 which is disposed in upstanding relation to the board fixing portion 3, and is adapted to be mounted on an outer surface of a connector housing of a connector, and a generally right-angularly-bent interconnecting portion 4 interconnecting the board fixing portion 3 and the housing mounting portion 2. This metal fixing member 1 is formed by bending a metal sheet of a generally rectangular shape into a generally cross-sectionally L-shape.
A method of fixing the connector to the mounting board by the metal fixing members 1 will be described, using FIG. 2 (which is a perspective view of one preferred embodiment of the invention) for convenience′ sake. First, the housing mounting portions 2 of the pair of metal fixing members 1 are mounted respectively on fixture mounting portions 41a formed respectively on opposite end surfaces of the connector housing 41. Then, the board fixing portions 3 of the two metal fixing members 1 are soldered respectively to lands 45 (each made of a metallic foil) formed on the wiring board 43. Thus, the connector housing 41 is fixed to the wiring board 43 by the pair of metal fixing members 1.
When an external force, tending to separate the connector from the wiring board 43 in a direction of arrow A (in FIG. 9), is applied to the connector, this external force acts on solder 47, interposed between the board fixing portion 3 and the land 45 on the wiring board 43, via the housing mounting portion 2 and the interconnecting portion 4 of the metal fixing member 1, and tends to separate or tear the board fixing portion 3 from the wiring board 43. At this time, stresses concentrate particularly on solder 47a interposed between that region of the board fixing portion 3, disposed adjacent to the interconnecting portion 4, and the land 45. Therefore, when the external force, exceeding the joining strength of the solder, is applied, first, breakage develops in the solder 47a interposed between the region of the board fixing portion 3, disposed adjacent to the interconnecting portion 4, and the land 45 (For example, the solder 47a is separated from the board fixing portion 3).
Then, the breakage of the solder 47, starting from the solder 47a, proceeds sequentially toward a distal end edge of the board fixing portion 3 (in a direction of arrow B in FIG. 9), since the metal fixing member 1 has the generally L-shaped cross-section such that the board fixing portion 3 extends from one side edge of the interconnecting portion 4 in a direction of the thickness of the housing mounting portion 2. Therefore, there has been encountered a problem that the force of fixing of the metal fixing member 1 to the wiring board 43 is not necessarily sufficient.
In order to secure the sufficient fixing force for the metal fixing member 1, it may be proposed to increase the area of the board fixing portion 3 so as to increase the area of joining of the board fixing portion 3 to the land 45 on the wiring board 43, or it may be proposed to increase the width of the board fixing portion 3 so as to reduce the degree of concentration of the stresses on the solder 47a interposed between the region of the board fixing portion 3, disposed adjacent to the interconnecting portion 4, and the land 45. However, there has been encountered a problem that these measures can not meet the requirements of the compact design and space-saving design of the metal fixing member 1.